Power transmission and transformation technologies are critical for electrical power to be transmitted from power plants to users. At present, the entry standard of a household power grid is 220V/50 Hz or 110V/60 Hz. As the power grid for buildings or communities is complex, the entry voltage needs to be filtered and isolated so as not to affect the operation of the household power grid, to thereby guarantee that both the entry voltage and frequency meet the requirements.
A household power grid is a type of power line network and involves various electric appliances. While a majority of the electric appliances, such as electric lamps, switches and outlets, involve switches, other electric appliances, like refrigerators and air conditioners, involve multiple states. Specifically, most commonly used household appliances and elements are classified to be single-state, dual-state and multi-state. Single-state electric appliances include outlets, monitoring cameras, etc.; dual-state electronic appliances include electric lamps, switches, optical sensors, acoustic sensors, outlets with a switching function, etc.; and multi-state electric appliances include temperature-adjustable air conditioners, refrigerators, light intensity-adjustable electric lamps, and the like.
A well-managed household power grid lays a foundation for modern smart home, which not only requires functional diversity, managerial convenience, and ease for use, but also requires quick design and installation, and material efficiency, in order to satisfy the requirement of modern cities for low-carbon life. Currently, switches of household appliances are generally controlled on-site manually, and some more advanced ones are controlled through a tangible remote controller. It is hard to achieve off-site control and arbitrary control over different electric appliances.
It remains to be solved as how to achieve intelligent management over these electric appliances, how to improve the security of smart home, how to prevent intrusion, and how to lower the cost.